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Commit ca785ec6 authored by Jan Kara's avatar Jan Kara Committed by Mark Fasheh
Browse files

quota: Introduce DQUOT_QUOTA_SYS_FILE flag 



If filesystem can handle quota files as system files hidden from users, we can
skip a lot of cache invalidation, syncing, inode flags setting etc. when
turning quotas on, off and quota_sync. Allow filesystem to indicate that it is
hiding quota files from users by DQUOT_QUOTA_SYS_FILE flag.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent dcb30695

fs/dquot.c

+30 −15
Original line number Diff line number Diff line
@@ -1631,6 +1631,11 @@ int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags) 
		dqopt->ops[cnt] = NULL;

	}

	mutex_unlock(&dqopt->dqonoff_mutex);



	/* Skip syncing and setting flags if quota files are hidden */

	if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)

		goto put_inodes;



	/* Sync the superblock so that buffers with quota data are written to

	 * disk (and so userspace sees correct data afterwards). */

	if (sb->s_op->sync_fs)
@@ -1655,6 +1660,12 @@ int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags) 
				mark_inode_dirty(toputinode[cnt]);

			}

			mutex_unlock(&dqopt->dqonoff_mutex);

		}

	if (sb->s_bdev)

		invalidate_bdev(sb->s_bdev);

put_inodes:

	for (cnt = 0; cnt < MAXQUOTAS; cnt++)

		if (toputinode[cnt]) {

			/* On remount RO, we keep the inode pointer so that we

			 * can reenable quota on the subsequent remount RW. We

			 * have to check 'flags' variable and not use sb_has_
@@ -1667,8 +1678,6 @@ int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags) 
			else if (!toputinode[cnt]->i_nlink)

				ret = -EBUSY;

		}

	if (sb->s_bdev)

		invalidate_bdev(sb->s_bdev);

	return ret;

}
@@ -1715,25 +1724,31 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, 
		goto out_fmt;

	}



	/* As we bypass the pagecache we must now flush the inode so that

	 * we see all the changes from userspace... */

	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {

		/* As we bypass the pagecache we must now flush the inode so

		 * that we see all the changes from userspace... */

		write_inode_now(inode, 1);

	/* And now flush the block cache so that kernel sees the changes */

		/* And now flush the block cache so that kernel sees the

		 * changes */

		invalidate_bdev(sb->s_bdev);

	}

	mutex_lock(&inode->i_mutex);

	mutex_lock(&dqopt->dqonoff_mutex);

	if (sb_has_quota_loaded(sb, type)) {

		error = -EBUSY;

		goto out_lock;

	}

	/* We don't want quota and atime on quota files (deadlocks possible)

	 * Also nobody should write to the file - we use special IO operations

	 * which ignore the immutable bit. */



	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {

		/* We don't want quota and atime on quota files (deadlocks

		 * possible) Also nobody should write to the file - we use

		 * special IO operations which ignore the immutable bit. */

		down_write(&dqopt->dqptr_sem);

		oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);

		inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;

		up_write(&dqopt->dqptr_sem);

		sb->dq_op->drop(inode);

	}



	error = -EIO;

	dqopt->files[type] = igrab(inode);

fs/quota.c

+3 −0
Original line number Diff line number Diff line
@@ -160,6 +160,9 @@ static void quota_sync_sb(struct super_block *sb, int type) 
	int cnt;



	sb->s_qcop->quota_sync(sb, type);



	if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)

		return;

	/* This is not very clever (and fast) but currently I don't know about

	 * any other simple way of getting quota data to disk and we must get

	 * them there for userspace to be visible... */

include/linux/quota.h

+7 −0
Original line number Diff line number Diff line
@@ -332,6 +332,13 @@ enum { 
#define DQUOT_SUSPENDED		(1 << _DQUOT_SUSPENDED)

#define DQUOT_STATE_FLAGS	(DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED | \

				 DQUOT_SUSPENDED)

/* Other quota flags */

#define DQUOT_QUOTA_SYS_FILE	(1 << 6)	/* Quota file is a special

						 * system file and user cannot

						 * touch it. Filesystem is

						 * responsible for setting

						 * S_NOQUOTA, S_NOATIME flags

						 */



static inline unsigned int dquot_state_flag(unsigned int flags, int type)

{